1. Technical Field
The present invention generally relates to vehicle control systems and more particularly to a vehicle control system that utilizes data from global positioning satellites for enhanced performance.
2. Discussion
It is well known in the art that the performance of vehicle control systems, such as anti-lock brake systems, traction control systems and stability systems, are effected by a diverse number of factors that are difficult to monitor and/or detect. These factors include, for example, the type of road on which the vehicle is operating and the weather conditions in which the vehicle is being operated. When information such as this is known by the vehicle control system, the vehicle control system is able to tailor its response in a predetermined manner so as to improve its effectiveness.
One approach to providing vehicle control systems with environmental information entails a process of learning or recognizing characteristics that are indicative of a particular situation. This approach, however, has several drawbacks. First, these processes tend to be iterative in nature and as such, a lag time typically exists between the point at which the environmental conditions change and the point at which these systems achieve their maximum performance level.
A second drawback relates to the ability of these systems to precisely detect the environmental conditions in which they are being operated. For example, it is common for traction control systems to use wheel slip to determine the road surface type and/or the road surface condition. Wheel slip of a given magnitude may indicate that the vehicle is being operated on a snow-covered surface, causing the traction control to limit the torque that is delivered to the vehicle drive wheels in a desired manner. Operation of the vehicle on a sand-covered surface will provide wheel slip data that is generally indistinguishable from the wheel slip data that is generated for a snow-covered surface, causing the traction control system to operate as if the vehicle was operating on a snow-covered surface. This situation, however, the performance of the traction control system is substantially impaired as it is desirable in such situations to maximize wheel torque rather than minimize it.
In view of these limitations, another approach has been suggested wherein cameras are employed to directly determine various environmental conditions. While it is permissible to provide enhanced performance in some situations using this approach, several drawbacks have been noted. The first concerns the robustness of a system that employs optical equipment in a vehicular environment to monitor the environment in which the vehicle is operated. As with any use of optics, it is essential that the optics, whether it be the lens of the device or a protective device that covers the lens, remain clean so as to provide accurate and reliable data. Regardless of the placement of such devices, constant attention to the cleanliness of the optics must be paid to assure that the optical device is functioning properly.